spike.cfg : remote_bitbang host localhost should be remote_bitbang_host in OPENOCD's

[yesuweiYYYY]

In readme.md

In a separate shell run OpenOCD with the appropriate configuration file:
$ cat spike.cfg
adapter driver remote_bitbang
remote_bitbang host localhost
remote_bitbang port 9824
...
"remote_bitbang host localhost" should be "remote_bitbang_host localhost"
"remote_bitbang port 9824" should "remote_bitbang_port 9824"